Video encoding device and video decoding device using high-precision skip encoding and method thereof
Provided is a video decoding method performed by a video decoding apparatus, the video decoding method including: determining prediction mode information of a current block and an index indicating a prediction candidate, from a bitstream; determining a prediction candidate list according to the prediction mode information; when the prediction mode information of the current block indicates a pre-set prediction mode, determining a motion vector indicated by the index indicating the prediction candidate from the prediction candidate list, and determining a prediction motion vector of the current block based on at least one of pieces of motion prediction information related to the motion vector; and determining a motion vector of the current block based on the prediction motion vector, wherein the pre-set prediction mode is a prediction mode different from a skip mode and a merge mode.
1. A video decoding apparatus comprising:
a determiner configured to:
obtain, from a bitstream, a skip mode flag indicating whether a current block is predicted in a skip mode,
in response to the skip mode flag indicating that the current block is not predicted in the skip mode, obtain, from the bitstream, a merge mode flag,
in response to determining whether the merge mode flag indicates that the current block is predicted in a merge mode or not, obtain, from the bitstream, motion vector prediction mode information of the current block, and
when the motion vector prediction mode information of the current block indicates a pre-set prediction mode, obtain, from the bitstream, motion vector difference information and a first index indicating a prediction candidate from a first candidate list; and
a decoder configured to determine the first candidate list including prediction candidates corresponding motion vectors of blocks adjacent to the current block, determine a first motion vector candidate indicated by the first index from the first candidate list, determine a prediction motion vector of the current block based on the first motion vector candidate and the motion vector difference information, determine a motion vector of the current block based on the prediction motion vector, determine a predicted block of the current block indicated by the motion vector, determine a residual block of the current block by performing inverse transformation on transform coefficients of the current block and determine a reconstructed block of the current block by combining the prediction block and the residual block,
wherein the motion vector difference information comprises sign information and a pixel distance of the motion vector difference, the motion vector difference comprises a single component among an x-axis component and a y-axis component, and the pixel distance is a value of a sub-pel unit or an integer-pel unit, and
wherein, when the motion vector prediction mode information of the current block does not indicate the pre-set prediction mode, the determiner obtains, from the bitstream, a second index indicating a prediction candidate from a second candidate list, and the decoder determines the second candidate list including prediction candidates corresponding motion vectors of neighboring blocks of current block, determines a second motion vector candidate indicated by the second index from the second candidate list, and determines the prediction motion vector of the current block based on the second motion vector candidate, without using the motion vector difference information.
2. A video encoding apparatus comprising:
a prediction unit configured to:
generate a skip mode flag indicating whether a current block is predicted in a skip mode,
when the current block is not predicted in the skip mode, generate a merge mode flag indicating whether the current block is predicted in a merge mode,
in response to determining whether the current block is predicted in the merge mode or not, generate motion vector prediction mode information of the current block indicating whether the current block is predicted in a pre-set prediction mode,
when the current block is predicted in a pre-set prediction mode, determine a motion vector of the current block, determining a first candidate list including prediction candidates corresponding motion vectors of blocks adjacent to the current block, determine a first prediction candidate from the first prediction candidate list, determine a motion vector difference by subtracting the first prediction candidate from the motion vector of the current block, and generate information regarding the motion vector difference and a first index indicating the prediction candidate from the first candidate list, and
when the current block is not predicted in the pre-set prediction mode, determine a second candidate list including prediction candidates corresponding motion vectors of neighboring blocks of the current block, determining a second prediction candidate corresponding to the motion vector of the current block among the second candidate list and generate a second index indicating the second prediction candidate from the second candidate list, without generating the information regarding the motion vector difference; and
a transformation unit configured to determine a residual block by subtracting a predicted block of the current block indicated by the motion vector from the current block, and generate transform coefficients of the residual block of the current block by performing transformation on the residual block,
wherein the information regarding the motion vector difference comprises sign information and a pixel distance of the motion vector difference, the motion vector difference comprises a single component among an x-axis component and a y-axis component, and the pixel distance is a value of a sub-pel unit or an integer-pel unit.